The invention relates to an apparatus for filling containers with a liquid or solid flowing medium, and particularly for filling drums or barrels sealed with screw plugs or other plugs, especially screw plugs covered by slipped-on safety caps.
Various apparatuses are known for simultaneously filling receptacles, such as containers, drums, packs or the like, with liquid or flowable solid media.
European Patent Specification EP-A-No.-0 105 197 discloses such a filling apparatus, which includes a pipe system with a feed pump for supplying the medium to be filled, and filling valves connected by means of supply lines above the receptacle to be filled. Each supply line leading to the filling valves includes a volume changer with an impeller arranged in its interior and rotated by the medium flowing to the particular filling valve. The impellers of all the volume chambers are rigidly interconnected by means of a mechanical shaft connected to a breaking apparatus controllable by means of a system pressure-dependent control device. To control the filling valves a two-stage pneumatic control cylinder is directly connected with at least one filling valve and is connected to the other filling valves by means of an adjusting device. A control member responds to the weight of the filled medium by means of a balance associated with one of the filling valves and is connected to the control cylinder. Such a filling apparatus makes it possible to simultaneously fill several receptacles, while it is only necessary to measure and monitor the filling volume or weight of a single receptacle.
U.S. Pat. No. 3,548,891 discloses a plant for simultaneously filling several receptacles, but using dosing and filling apparatus in a number corresponding to the number of containers to be filled, with an individual filling arrangement associated with each of the containers to be filled. The filling connections used in this plant make it possible to fill individual containers in accordance with the filling volume. This is made possible by a filling arrangement associated wtih each individual container. However, in the case of this filling arrangement neither the filling volume, nor the filling weight of an individual container is measured and monitored, so that the filling of the containers is not controlled by means of the filling volume or weight of an individual container. In this filling plant, the filling volume or weight of each individual container is monitored and used for controlling the filling arrangement.
U.S. Pat. No. 3,205,920 discloses a filling apparatus making it possible to pour liquids into containers which are moved past several filling valves. The containers to be filled travel on a conveyor belt, whose forward movement stops if the number of containers corresponding to the number of filling valves is located under the discharge openings of the latter. At this instant a link motion simultaneously places all the filling valves on the openings of the containers to be filled and pumps simultaneously supply the filling valves with that liquid quantity which is to fill containers. In order to ensure uniform setting of the filling valves onto the container openings, all the filling valves are fixed to a supporting beam, which travels in vertical guides. The link motion allows the supporting beam to move the filling valves up and down. The filling valves are connected to the pump by means of flexible hose line. Once again, this filling apparatus simultaneously fills all the containers with liquid using filling valves which simultaneously perform dosing.
Drums intended to be filled with liquids are, as is known, supplied with screwed down plugs. It is therefore necessary to remove the latter and then screw them down again after filling. Thus, the drums must be precisely aligned on the feed belt or the like of the filling arrangement. Otherwise there is a risk that the filling material will flow down the drum and not into the bunghole.
Disclosure of an apparatus for closing the fill opening of a drum or the like with a device for inserting and fixing a plug in the opening appears in DE-A-No.-1,817,237. Here a closing or sealing apparatus includes both a device for inserting the plug and also a position determining device fitted and spaced so that they can freely move up and down, as well as in accordance with polar co-ordinates with respect to a fixed point in a plane at right angles to the upwardly and downwardly directed movement. In addition, a gripping arrangement prevents free movement of inserting device and the positioning device. When the gripping arrangement prevents the free movement of the inserting and positioning devices a drive arrangement is able to move the two devices, but only linearly and in forced manner over a distance corresponding to the spacing between the two devices. This closing device has very large dimensions.
U.S. Pat. No. 2,731,185 discloses a plug screw-in device with a centering and screw-in head, which includes an outer centering ring and a screw-in head displaceable therein counter to spring tension. A drive shaft connects the head with angularly movable joints to a drive. The centering ring is constructed and profiled such that on screwing a plug into the bunghole of the drum it is supported on the upper circumferential rim of the bunghole connection and therefore is adapted to the dimensions and diameter of the bunghole connection.
European Specification EP-A-No.-0 065 180 discloses a plug screw-in device for drums having a centering and screw-in head, comprising an outer centering ring and a screwhead located in its interior and displaceable against spring tension and which is connected to its drive apparatus by means of a drive shaft having an angularly movable joint. This plug screw-in device includes a supporting frame and an upper mounting plate and a lower mounting plate on which is arranged a centering plate, which is provided with a cross-shaped opening and whose inner wall surface bounding the opening tapers conically towards the centering and screw-in head and passes at the bottom into a vertical wall section. The internal diameter of the recess defined by the wall section is larger than the diameter of the drive shaft. In the opening is placed a correspondingly profiled molded or shaped body with an outer wall surface tapering conically in the direction of the centering rings supported on the drum cover plate during the plug centering rings supported on the drum cover plate during the plug and screw-in process and is connected by a portion located on the plate to a guide plate. The latter is held on at least three guide bolts fixed to the lower mounting plate of the supporting frame so as to be longitudinally displaceable and pivotable against the tension of springs. The drive shaft includes a shaft part connected to the drive apparatus and a shaft part carrying the screw-in head, the two shaft parts being interconnected by means of a universal joint.
All the filling plants operate in the same way, namely following the alignment of the container to be filled by means of a screw-in arrangement, the screw plug is screwed out of the container filling opening, picked up and placed on a conveyor belt, which runs parallel to the feed path of the container to be filled. The screw plugs removed from the screw-in apparatus and placed on the conveyor belt are brought into a new position parallel to the feed movement of the containers to be filled, in which the screw plug is screwed into the fill opening of the filled container and the screw in-in apparatus for the screw plugs can also participate in this forward or advance movement if no second screw-in apparatus is provided. When the screw plug has been unscrewed, then the empty container is supplied on a conveying apparatus to a filling station and stays therein until the container has been filled with the corresponding filling material. The filled container then passes into the screw plug screw-in position, where the screw-in apparatus is kept ready. In this position, it is simultaneously possible to supply safety caps, which of corresponding mechanism mounts on the screw plug screwed into the fill opening of the filled container. In such a filling plant there are three work cycles, namely in the first cycle the drum is aligned and the screw plug is unscrewed from the filling opening. Following a further advance of the thus prepared container, in the second work cycle the container is filled. Followed a further advance of the filled container, in a third work cycle the fill opening is sealed by means of a screw plug and optionally the safety cap is fitted. A thus contracted and functioning filling plant has relatively large dimensions, even though satisfactory working speeds are achieved. In addition, the operating efficiency of such a filling plant is dependent on the filling time and the number of work cycles. Furthermore, there is no need in the case of such filling plants to align the containers with the screw-in apparatus and the filling apparatus in a very accurate manner. An extremely accurate alignment or orientation of the containers is necessary only for fitting the safety cap on the already screwed in screw plugs.